M4 motorway diversion around Newport, Gwent

Tagged with: Casework status: Closed Casework type: Transport Site designations: SAC Site designations: SSSI
Water vole, Arvicola amphibius, Peak District, UK


An M4 motorway diversion around Newport, sometimes called the “M4 relief road”, has been considered since the early 1980s. The Welsh Government consulted on draft Orders for the development of the diversion (also known as ‘the Black route’, following previous consultations on route options) in 2016. Thousands of objections were submitted, including over 5000 by RSPB supporters, and consequently the Welsh Government announced a local public inquiry which opened on 28 February 2017.

The RSPB submitted written evidence to the public inquiry objecting to the proposal on the basis that the new section of motorway would cut through four of the Gwent Levels Sites of Special Scientific Interest (SSSIs), destroying and fragmenting habitats. It would have destroyed the area used by a pair of common crane which has returned to breed on the Levels (the first in Wales for 400 years) and it would have jeopardised the future of one of the UK’s rarest bees, the shrill carder bee.

The proposal ran contrary to the Welsh Government's specific legal duties relating to SSSIs and its duties to biodiversity under the Environment (Wales) Act 2016. It was also contrary to the requirements and the spirit of Wales’ world-leading Well-being of Future Generations Act, which calls for a new approach recognising the importance of the environment to Wales’ future well-being.

The Public Inquiry ran from February 2017 to March 2018. In summary the Inspector concluded that whilst there was an unavoidable adverse impact on the Gwent Levels SSSIs this, weighed against the vital national infrastructure importance of the proposals, meant the wider benefit of the M4 Relief Road would not have a "disproportionate adverse impact". The Inspector therefore allowed the proposal.

The scheme then went to the First Minister and at this stage Mark Drakeford AM held that whilst the scheme was no longer financially viable in any case, he, as First Minister, disagreed with the Inspectors decision and afforded greater weight to the environmental impact. In his judgement the projects adverse impact on the environment outweighed the advantages of the new road.


Why is it worth fighting for?

We were concerned about the M4 proposals because, in our opinion, it would damaged the fragile wetlands of the Gwent Levels.

It's not just the road itself which would have had an effect, but there would have been damage indirectly through isolating parts of the Gwent Levels from the main body of the wetland, causing fragmentation of this important habitat. Furthermore, it could have seriously harmed the wetlands' water supply, and polluted the watercourses upon which the wetlands rely.

We were also worried about the precedent this huge project would have set in terms of a move away from sustainable transport to car-borne transport, with the resultant increases in greenhouse gases.

We think the Welsh Government did not properly looked at more environmentally-acceptable alternatives to this project, and has did not take into account the fact that traffic levels on the existing M4 have remained more or less static for several years. We further consider that the project went against the aims of the recent Well-being of Future Generations Act.

Gwent Levels RSPB Reserve, aerial view


RSPB Cymru applauded the First Minister’s bold decision which we believe shows the Welsh Government’s true commitment to sustainable development and to reversing the decline in biodiversity.

We now await the recommendations of the South East Wales transport commission and hope that more sustainable transport solutions will prevent the damaging motorway proposal being brought back in the future.

Following the First Minister's decision, the SE Wales Transport Commission was set up to review the alternatives to the M4 Relief Road. The remit of the Commission is to find alternative, sustainable solutions to overcoming the congestion issues between junctions 24 – 28. It has been made clear by the First Minister that these alternative solutions are not to be judged against the previous M4 Relief Road but instead are to comprise sustainable alternatives in their own right.

Whilst the Commission are still in the process of reviewing data and gathering evidence a few recent fast-tracked measures have been announced, including but not limited to;

  • Average speed camera installation to limit traffic to 50 mph and removal of the variable speed limit
  • Additional signage for alternative routes
  • Bollards to help lane discipline in key areas

The Commission is due to meet again in March to discuss findings and evidence collated to date.


  • 4 June 2019
    First Minister Mark Drakeford AM declined to make the Schemes and Orders, therefore overturning the Inspectors recommendation.
  • 21 September 2018
    Inspector approved all of the relevant Schemes and Orders applied for under the Highways Act 1980.
  • 28 February 2017 - March 2018
    Local Public Inquiry in progress at Lysaght Institute, Newport. RSPB provided detailed written evidence and has attended a site visit with the Inspector to demonstrate our concerns. 
  • 2016
    Welsh Government consulted on draft orders and they received thousands of objections, including over 5,000 from RSPB supporters. This led to the Government opening a Local Public Inquiry.
  • 10 - 12 March 2015
    Judicial Review of the Welsh Government's plans to build a new £1 billion motorway across the protected Gwent Levels.
  • 23 September 2014
    Legal challenge launched by Friends of the Earth Cymru against the Welsh Government’s decision to build the £1 billion motorway through the Gwent Levels.
  • 16 December 2013
    Public consultation ends (see Useful links)
  • 23 September 2013
    Consultation on upgrade to M4 around Newport opens
  • 26 June 2013
    Welsh Government Minister for Transport Edwina Hart AM announced the Government's intention to consult later in the year on a new motorway to the South of Newport
  • 6 March – 6 July 2012
    Welsh Government Consultation on M4 Corridor Enhancement Measures

Further reading